The present invention relates to a rotating vehicle seat that is designed so that passengers, such as the elderly or the handicapped, can easily get in or out of a vehicle.
A rotating seat of this type has been constructed to be rotated to the side of a door opening with an occupant held in a seated position (as disclosed, for example, in Japanese Laid-Open Utility Model Publication No. 61-57047 and Japanese Laid-Open Patent Publication No. 62-173343). The rotating vehicle seat is typically disposed as far to the rear as possible in order to provide a wide space close to the occupant""s feet. Therefore, the seats in the front and the rear, for example in a four-door sedan car, are disposed such that the seats are masked beside the center pillars and the rear pillars.
Therefore, if the seat is rotated while in the initial seated position, the pillar that is positioned beside the seat interferes with the rotation of the seat to the entry/exit position. Therefore, with the known rotating seat, the rotating seat is first moved forward in order to be moved outside of the range of interference with the pillar. Thereafter, the seat is rotated to the door opening side.
Thus, the known rotating seat is poor in usability because it requires troublesome operations of moving the rotating seat forward and then rotating it to the side of the door opening. Further, if the seat is positioned near the front, such that the seat can be rotated while in the seated position, the space close to occupant""s feet will be sacrificed and the occupant will be forced to sit in an uncomfortable position.
The present invention has been made in view of the above problems, and its object is to provide a rotating vehicle seat having excellent usability without sacrificing the space close to the occupant""s feet.
To this end, the invention according to claim I provides a rotating vehicle seat that includes a rotating support base for rotatably supporting a seat body, a longitudinal support base for supporting and moving the rotating support base in a longitudinal direction of the vehicle, and coupling means disposed between the seat body and the longitudinal support base for coupling the rotational movement and the longitudinal movement of the seat body.
According to this rotating vehicle seat, when the seat body is rotated to the door opening side by means of the rotating support base, the seat body moves forward while rotating by means of the longitudinal support base that is coupled to the rotating support base by the coupling means. Therefore, even if the seat body is located in the rearmost position in order to provide a wide space close to the occupant""s feet, by a simple rotational operation, the seat body can be rotated to the door opening side without interfering with a pillar or other portions of the vehicle. In other words, unlike the known rotating seat, it is not necessary to perform two operations of rotating the seat body and moving the seat body forward. Consequently, with the rotating vehicle seat according to claim 1 of the invention, it is possible to greatly improve usability while providing a wider space close to the occupant""s feet.
The invention according to claim 2 provides the rotating vehicle seat as defined in claim 1, wherein the coupling means comprises a pinion gear that rotates together with the seat body, and a rack mounted on the longitudinal support base along the longitudinal direction thereof for engaging with the pinion gear.
According to this rotating vehicle seat, the rotational movement and the longitudinal movement of the seat body are coupled to each other by engaging the pinion gear on the seat body with the rack on the longitudinal support base. Therefore, the same effect as the construction of claim 1 can be obtained.
The invention according to claim 3 provides the rotating vehicle seat as defined in claim 1, wherein the coupling means comprises a pinion gear that rotates together with the seat body, an intermediate gear rotatably mounted on the rotating support base, and a rack mounted on the longitudinal support base along the longitudinal direction thereof, the pinion gear engaging with a small gear portion of the intermediate gear and the rack engaging with a large gear portion of the intermediate gear, whereby the rotational movement of the seat body is amplified by a ratio corresponding to a gear ratio of the large gear portion to the small gear portion and is transmitted to the longitudinal movement of the seat body.
According to this rotating vehicle seat, because the rotational movement of the seat body is amplified by a ratio corresponding to the gear ratio of the large gear portion to the small gear portion of the intermediate gear and is transmitted to the longitudinal movement of the seat body, the distance of the longitudinal movement of the seat body can be longer compared with a construction in which the pinion gear is directly engaged with the rack. The distance of the longitudinal movement, which can be coupled during the same 90xc2x0 rotational movement of the seat body, can be set to a desired distance by changing the gear ratio of the small gear portion to the large gear portion of the intermediate gear. Thus, when applying this design to various types of vehicle, the rotating seat can provide the necessary amount of movement in the longitudinal direction to ensure a sufficient space close to the occupant""s feet, so that the general versatility of the coupling means and the rotating seat can be enhanced.
The invention according to claim 4 provides the rotating vehicle seat as defined in claim 2 or 3, wherein the pinion gear has a non-toothed portion so that a range is provided in which the longitudinal movement is not coupled to the rotational movement of the seat body, which range is provided within the total range of rotational movement of the seat body.
According to this rotating vehicle seat, because a predetermined range in which the longitudinal movement is not coupled to the rotational movement of the seat body is provided within an initial range to start the seat body rotating from the seated position, the seat body does not move within this initial rotation range. After being rotated by a predetermined angle, the seat body can be moved forward by coupling with the rotational movement. By providing such a seat body that performs sophisticated movements, for example in a vehicle for which the occupant""s feet will interfere with a front seat, a pillar, an opened door or other portions if the seat body is moved forward from the beginning of rotation, the seat body can be rotated only at the beginning, and after moving the occupant""s feet to the outside of the door opening, the seat body can be moved forward. As a result, the seat body can rotate while preventing the occupant""s feet as well as the seat body from interfering with a pillar or other portions.
The invention according to claim 5 provides the rotating vehicle seat as defined in claim 4, further comprising a slide lock mechanism for preventing the longitudinal movement of the seat body, the slide lock mechanism being constructed to be automatically released when the rotational movement and the longitudinal movement of the seat body are coupled to each other.
According to this rotating vehicle seat, the longitudinal movement of the seat body can be coupled to the rotational movement without the need to operate a commonly incorporated longitudinal slide lock mechanism. In this respect, usability can be further improved.
The invention according to claim 6 provides the rotating vehicle seat as defined in claim 1, wherein the coupling means comprises a link arm, one end of which is rotatably connected to the underside of the seat body at a position off center of the rotation of the seat body and the other end is rotatably connected to the longitudinal support base, whereby the first end of the link arm moves around the other end of the link arm and in the longitudinal direction of the vehicle as the seat body rotates, so that the seat body is moved in the longitudinal direction of the vehicle.
According to this rotating vehicle seat, because one end of the link arm moves around the center of rotation of the seat body when the seat body is rotated, while the other end of the link arm does not move, the seat body moves longitudinally with respect to the vehicle while rotating. Thus, the same effect as the construction of claim 1 can be obtained.
The invention according to claim 7 provides the rotating vehicle seat as defined in claim 1, wherein the coupling means comprises a wire, one end of which is secured to the underside of the seat body and the other end is secured to the longitudinal support base, whereby the seat body is moved in the longitudinal direction of the vehicle by winding the wire as the seat body rotates.
According to this rotating vehicle seat, when the wire is wound at the end thereof and shortened by the rotational movement of the seat body, the seat body moves, for example, frontward with respect to the vehicle. When the seat body is rotated in the reverse direction to release the winding, the wire is drawn out so that the seat body can be moved, for example, rearward with respect to the vehicle.
The invention according to claim 8 provides the rotating vehicle seat as defined in claim 1, further comprising a lateral support base for moving the seat body in a lateral direction of the vehicle, the lateral support base being constructed to move the seat body to a lower position as the seat body moves to the exterior in the lateral direction of the vehicle.
According to this rotating vehicle seat, because the seat body is displaced to a lower level than in the interior position when the seat body moves to the exterior of the door opening, the occupant can easily sit on and rise from the seat body. This is particularly useful when the occupant moves between a wheel chair and the seat body.
The invention according to claim 9 provides the rotating vehicle seat as defined in claim 8, further comprising a longitudinal restriction member for restricting the longitudinal movement of the seat body during the lateral movement of the seat body.
According to this rotating vehicle seat, the longitudinal movement of the seat body is restricted by the longitudinal restriction member during the lateral movement of the seat body. When the longitudinal movement is restricted, the coupled rotational movement is also restricted. Thus, the longitudinal movement and the rotational movement of the seat body are restricted when the seat body moves laterally of the vehicle, for example, from the interior to the exterior of the vehicle. Consequently, the seat body can be prevented from interfering with pillars on the both sides or other portions when passing through the door opening.
Various constructions may be applied as the longitudinal restriction member. For example, a restriction plate that serves as the longitudinal restriction member may be mounted on the lateral support base and configured to extend, for example, into the longitudinal moving range of the longitudinal support base throughout the entire lateral moving range of the seat body. With this construction, the longitudinal movement of the longitudinal support base can be prevented by interference of a portion of the longitudinal support base with the restriction plate.
The invention according to claim 10 provides the rotating vehicle seat as defined in claim 9, wherein the longitudinal restriction member also has a function of restricting the lateral movement of the seat body in the seated position.
According to this rotating vehicle seat, as the seat body moves to the exterior side by operation of the lateral support base, the seat body is gradually displaced to a lower position. Therefore, the seat body in the interior seated position will be displaced downward under its own weight unless restricted (i.e. natural drop). In order to restrict this natural drop, a brake-incorporated motor may be applied as a drive source for the lateral support base. The incorporated brake locking of the lateral support base can prevent the natural drop of the seat body.
Although the brake incorporated motor is larger in size and the cost is increased, with the construction according to claim 10, such a problem can be eliminated, because the lateral movement or natural drop of the seat body is prevented by the longitudinal restriction member, rather than by locking the motor as a drive source.
In order to restrict the lateral movement of the seat body in the seated position, the longitudinal restriction member may also be configured, for example, to extend into the lateral moving range of the longitudinal support base or the rotating support base or the seat body when the seat body is in the seated position.